The applicant is a neurologist and has extensive clinical experience in pediatric and adult neuromuscular diseases. This award will allow her to obtain the training and mentoring to become an independent clinical investigator focusing on neuromuscular disorders. The educational plan includes didactic courses covering epidemiology, statistics, clinical trial design and health policies. DMD is a relatively common fatal genetic disease in children, with equal incidence throughout the world. The goal of this research is to conduct therapeutic human clinical trials with chemicals shown to improve muscle strength in the mdx. The aims of the proposed research plan are: 1) to conduct a double-blind, placebo-controlled, three-arm clinical trial of creatine and L-glutamine in patients with DMD and to assess the effect of these compounds on muscle strength as measured by manual muscle testing (MMT), quantitative muscle testing (QMT) and other functional measurements. Aim 2 is to conduct a double-blind, placebo- controlled clinical trial of coenzyme Q10 (CoQ10) in patients with DMD to assess its effects on: a) muscle strength, measured by QMT, compound Medical Research Council (MRC) score and functional measures; b) exercise capacity, to be measured by a fatigability protocol; and c) quality of life, to be measures by the Child Health Questionnaire. Aim 3 is to validate the specificity of the pediatric QMT system measuring maximal voluntary isometric contraction sequentially in children with DMD. The studies will be conducted at Pediatric Clinical Research Center (PCRC) at the Children's National Medical Center (CNMC), satellite to Georgetown General Clinical Research Center (GCRC). Three cores of the PCRC will be involved: the Biostatistics Core, the Genetics Core Laboratory and the Bioanalytical Core Laboratory. In addition, to increase the statistical power of this study, the applicant has assembled an international collaborative group that will conduct identical protocols and submit the data to the study center at CNMC. Future studies will test several other drugs with potential to improve muscle strength in DMD.